Young T, Aukes J, Hughes R, Tang H
Queensland Health, Respiratory and Sleep Medicine, PO Box M103, Missenden Road, Camperdown, New South Wales, Australia, 2050.
Cochrane Database Syst Rev. 2007 Jul 18(3):CD006212. doi: 10.1002/14651858.CD006212.pub2.
Pulmonary emboli can have potentially fatal consequences. Inferior vena caval filters are metal alloy devices that mechanically trap fragmented thromboemboli from the deep leg veins en route to the pulmonary circulation. Filters in current clinical use are designed to be introduced (and in the case of retrievable filters, removed) percutaneously. Although their deployment seems of theoretical benefit, their clinical efficacy and adverse event profile is unclear.
To examine evidence for the effectiveness of vena caval filters in preventing pulmonary embolism (PE). Secondary outcomes were mortality, distal (to filter) thrombosis, and filter-related complications.
Searches were conducted in the Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched May 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2007), MEDLINE (1966 to May 2007), and EMBASE (1966 to May 2007). Filter manufacturers and clinicians interested in filters were contacted for information.
Controlled clinical trials (CCTs) and randomised controlled trials (RCTs) that examined the efficacy of filters in preventing PE were selected.
Three authors extracted information independently. Incidence figures were extracted from survival tables. Dichotomous outcomes were analysed as hazard ratio estimates.
One RCT met the inclusion criteria. The PREPIC trial was an open RCT of 400 participants with documented proximal deep vein thrombosis (DVT) or pulmonary embolism and who received concurrent anticoagulation.PREPIC demonstrated the efficacy of permanent caval filters in preventing PE at eight years (HR 0.37, 95% CI 0.17 to 0.79, in favour of the filter). No reduction in mortality was seen, but this reflected an older study population (mean age 73 years); the majority of deaths were due to cancer or cardiovascular causes. There was an increased incidence of DVT in the filter group (HR 1.52, 95% CI 1.02 to 2.27). No details were recorded of adverse events of filters. No CCTs suitable for inclusion were found.
AUTHORS' CONCLUSIONS: Limited generalisability prevents any conclusions to be drawn from PREPIC. PREPIC employed permanent filters and lacked statistical power to detect a reduction in PE over shorter and more clinically significant time periods. However, PREPIC demonstrated that permanent caval filters are associated with an increased risk of long term lower limb DVT. There is a marked paucity of evidence regarding caval filter outcomes when used within their currently approved indications. There is also a lack of retrievable filter trials. Further trials are needed to assess vena caval filter safety and effectiveness.
肺栓塞可能产生潜在的致命后果。下腔静脉滤器是金属合金装置，可机械性地拦截从下肢深静脉进入肺循环途中的破碎血栓栓子。目前临床使用的滤器设计为经皮置入（对于可取出滤器，则可经皮取出）。尽管其置入在理论上似乎有益，但临床疗效和不良事件情况尚不清楚。
研究腔静脉滤器预防肺栓塞（PE）有效性的证据。次要结局为死亡率、滤器远端血栓形成及与滤器相关的并发症。
检索了Cochrane外周血管疾病组专业注册库（最后检索时间为2007年5月）、Cochrane对照试验中央注册库（CENTRAL）（《Cochrane图书馆》2007年第2期）、MEDLINE（1966年至2007年5月）和EMBASE（1966年至2007年5月）。还联系了滤器制造商和对滤器感兴趣的临床医生以获取信息。
选择了研究滤器预防PE有效性的对照临床试验（CCTs）和随机对照试验（RCTs）。
三位作者独立提取信息。发病率数据从生存表中提取。二分结局作为风险比估计值进行分析。
一项RCT符合纳入标准。PREPIC试验是一项开放性RCT，纳入了400例有近端深静脉血栓形成（DVT）或肺栓塞记录且同时接受抗凝治疗的参与者。PREPIC试验表明，永久性腔静脉滤器在8年时预防PE有效（风险比0.37，95%可信区间0.17至0.79，滤器组更优）。未观察到死亡率降低，但这反映了研究人群年龄较大（平均年龄73岁）；大多数死亡是由癌症或心血管原因导致。滤器组DVT发病率增加（风险比1.52，95%可信区间1.02至2.27）。未记录滤器不良事件的详细情况。未找到适合纳入的CCTs。
由于普遍性有限，无法从PREPIC试验得出任何结论。PREPIC试验使用的是永久性滤器，缺乏检测在更短且更具临床意义的时间段内PE减少情况的统计学效力。然而，PREPIC试验表明，永久性腔静脉滤器与长期下肢DVT风险增加相关。关于腔静脉滤器在目前批准适应证范围内使用的结局，证据明显不足。也缺乏可取出滤器的试验。需要进一步的试验来评估腔静脉滤器的安全性和有效性。
